A281271 - OEIS

A281271

Expansion of Product_{k>=1} (1 + x^(5*k-2)).

1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 2, 0, 1, 1, 0, 2, 0, 1, 1, 0, 3, 0, 1, 2, 0, 3, 0, 1, 3, 0, 4, 1, 1, 4, 0, 4, 1, 1, 5, 0, 5, 2, 1, 7, 0, 5, 3, 1, 8, 0, 6, 5, 1, 10, 1, 6, 6, 1, 12, 1, 7, 9, 1, 14, 2, 7, 11, 1, 16, 3, 8, 15, 1

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OFFSET

0,22

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..10000

FORMULA

a(n) ~ exp(sqrt(n/15)*Pi) / (2^(8/5)*15^(1/4)*n^(3/4)) * (1 - (3*sqrt(15)/(8*Pi) + 11*Pi/(240*sqrt(15))) / sqrt(n)). - Vaclav Kotesovec, Jan 18 2017, extended Jan 24 2017

MATHEMATICA

nmax = 100; CoefficientList[Series[Product[(1 + x^(5*k - 2)), {k, 1, nmax}], {x, 0, nmax}], x]

nmax = 100; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 0; Do[If[Mod[k, 5] == 3, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}]; ], {k, 2, nmax}]; poly

CROSSREFS

Cf. A219607, A281243, A281272, A280454.

Sequence in context: A057556 A112761 A284320 * A284319 A281272 A147310

Adjacent sequences: A281268 A281269 A281270 * A281272 A281273 A281274

KEYWORD

nonn

AUTHOR

Vaclav Kotesovec, Jan 18 2017

STATUS

approved